Influência da adição de um subproduto da produção de sal (carago) e do tempo de cura nas propriedades mecânicas de um solo expansivo da Cidade de Mossoró/RN

Abstract

Expansive soils are found in various parts of the world. Their main characteristic is the volumetric variation due to the variation in moisture content. This is due to the presence of expansive clay minerals in the clay fraction of the soil. These volume variations cause damage to engineering works, which can range from small cracks to total structural compromise. These soils can be stabilized by adding materials that react with the clay and reduce or eliminate expansion. This research aimed to evaluate the influence of the addition of carago on the properties of expansibility and shear strength of an expansive soil in the city of Mossoró, in the state of Rio Grande do Norte (RN). For this purpose, geotechnical characterization, compaction, free expansion, expansion stress and direct shear tests were performed on soil mixtures with the addition of 5% and 10% carago. Regarding the influence of the addition of carago in the soil, it was possible to conclude that all samples with 10% carago showed a reduction in free expansion in relation to samples of pure soil, with emphasis on the 25% reduction in samples with 7 days of wet curing, in relation to samples of pure soil with the same time and type of curing. There was an increase in the expansion stress in all samples with carago subjected to dry curing in relation to pure soil, with the exception of the sample with 10% carago and no curing, which presented a value equal to that of pure soil. There was an increase in cohesion in all samples with the addition of carago in relation to samples with pure soil, with emphasis on the 624% increase in the sample with 10% carago and 7 days of dry curing. Regarding the curing time of the samples, it was concluded that the longer dry curing time increased the free expansion and expansion stress in all samples subjected to this type of curing. The longer wet curing time reduced cohesion, this indicates that the carago may lose cementing action over time; for lower percentages this occurs more quickly.